Rate of Malignancies in Thyroid Imaging After Benign Aspiration

Rate of diagnoses and cost following thyroid imaging after benign fine-needle aspiration.

Follow-up imaging of the thyroid after benign fine-needle aspiration (FNA) is costly and results only in a small rate of subsequent malignancy detection, according to a study published in the American Journal of Roentgenology.

Researchers from Pennsylvania, Maryland, and Michigan sought to determine patterns, the cost of imaging tumor surveillance, and the rate of subsequent cancer detection in patients after an FNA biopsy of the thyroid.

The study included patients who had a benign thyroid FNA biopsy between January 1, 1999, and December 31, 2003, as identified from an institutional pathology database. Information was gathered from electronic medical records on imaging tumor surveillance and subsequent cancer detection. Cost was determined using the facility total relative value unit and the 2014 Hospital Outpatient Prospective Payment System conversion factor.

The results showed that 1,685 patients were determined to have a benign thyroid FNA biopsy, 800 (47.5%) of whom underwent follow-up imaging. The total cost for the procedures was $879,347 or $1099 per patient:

 Number of ProceduresTotal Cost of Procedures
Thyroid ultrasound2,223$529,874
Ultrasound-guided thyroid FNA biopsies606$176,157
Thyroid scintigraphy78$39,622
Neck CTs168$80,580
Neck MRIs53$53,114








The mean length of follow-up was 7.3 years, during which time 19 (2.4%) patients were diagnosed with thyroid cancer at a cost of $46,281 per cancer. Seventeen (89.5%) were diagnosed with papillary carcinoma and two (10.5%) with Hurthle cell carcinoma.

The researchers concluded that although half of patients with a benign thyroid FNA biopsy underwent follow-up imaging, it was at considerable cost with a small rate of subsequent malignancy.